Hans Felt is known as a Nuremberg compass maker (he became master in 1564) who made sundials in the 1560s. His maker's mark has been described as an acorn or a jester's hat.
E. Zinner, Deutsche und Niederl?ndische astronomische Instrumente des 11. bis 18. Jahrhunderts (2nd ed., Munich, 1967), p. 314; P. Gouk, The Ivory Sundials of Nuremberg 1500-1700 (Cambridge, 1988), p. 64.
Polyhedral Dial, Attributed to Hans Felt, Nuremberg, circa 1550 (London, BM)